Tailoring surface-supported water-melamine complexes by cooperative H-bonding interactions

Area of Science:

• Surface Science
• Photocatalysis
• Materials Chemistry

Background:

• Carbon nitride heterocycles are theoretically studied for water-splitting photocatalysis.
• Proton-coupled electron transfer (PCET) is a key reaction mechanism.
• Understanding water-catalyst binding is essential for accurate theoretical models.

Purpose of the Study:

• To characterize the water-catalyst binding configuration on a melamine/Cu(111) interface.
• To validate and improve theoretical models of water-splitting photocatalysis.
• To elucidate the role of melamine in stabilizing water adsorption.

Main Methods:

• Adsorption of water on a monolayer of melamine grown on Cu(111) under ultra-high vacuum (UHV).
• X-ray photoemission spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy.
• Density functional theory (DFT) calculations.

Main Results:

• Melamine on Cu(111) adopts a tilted configuration with a dangling amino group.
• Water adsorption causes a shift in the N 1s binding energy of melamine.
• DFT calculations confirm a cooperative binding mechanism involving two adjacent melamine molecules.

Conclusions:

• A well-defined water/melamine/Cu(111) interface was created and characterized.
• Two adjacent melamine molecules stabilize the water-catalyst complex through hydrogen bonding.
• This study provides crucial experimental and theoretical insights into water-catalyst interactions for photocatalysis.